Showing posts with label Personal computer. Show all posts
Showing posts with label Personal computer. Show all posts

Friday, December 11, 2009

Social Ramifications

For most of us, we cannot imagine a daily existence that lacked basic necessities such as electricity, hot water, indoor plumbing, natural gas, and so on. However, people living 100 years ago would have considered these modern conveniences to be a luxury. Nowadays, we take these things for granted. Can you imagine living in a world without them? That sensation—a bizarre and barbaric “how could you live like that” feeling—is the way that people will view our lives 100 years from now. Bandwidth is quickly becoming a “fourth utility,” comparable to electricity, water, and gas. In the future, people will just expect it to be there… anything less will simply be “uncivilized.”
Many decades ago, computers were thought of as stand-alone tools. While first used as business devices, they eventually filtered into home life for utility and recreational purposes. As computing evolved, the idea that computers could interact and “network” together grew in popularity. Before the advent of the Internet, computers were networked to share files and devices, such as printers. Early networking attempts were focused on lowering hardware peripheral costs. For example, by networking an entire business you could

Thursday, November 26, 2009

802.11g

To keep up with the 54-Mbps speed claims of 802.11a, the 802.11g protocol was ratified in 2003. This protocol took the OFDM modulation technique of 802.11a and applied it to the 2.4 GHz spectrum of 802.11b. Because it operated in 2.4 GHz, it was possible to remain backwards-compatible with 802.11b equipment. 802.11g radios support both OFDM and DSSS modulation techniques. Therefore, an 802.11g device would, in theory, be compatible with an original 1 or 2 Mbps 802.11 DSSS device from 1997.
Keep in mind that a typical residential or small business hotspot has a DSL or similar connection behind it providing the bandwidth to the Access Point.These broadband connections typically provide speeds in the 1.5 to 3 Mbps range. Obviously, the bottleneck in a Wi-Fi deployment is usually the DSL (or even T1) pipe.Therefore, the advantages of higher speed wireless connections (such as 802.11g) are often limited because of the Internet connection.The only exception would be if there is a large number of data transfers between wireless clients and PCs on the local area network (or between two wireless PCs). In those cases (such as gaming or local file transfers), users will notice a significant speed increase when using 802.11g,  compared to slower wireless protocols, such as 802.11b. In many large-scale community wireless networks, a system of repeaters will be used to enhance coverage in dead spots. Because each repeater (such as WDS) reduces the bandwidth by half, using 802.11g (and 54 Mbps) is often desirable.The logic here is that you can halve 54 Mbps more times then you can halve 11 Mbps, and yet still wind up with a useable, decent bandwidth speed for the client.
The pros and cons of 802.11g are as follows:
  • Upside: Relatively fast speed; compatible with 802.11b
  • Downside: Interference from other 2.4 GHz devices; only three non-overlapping channels